The present invention relates to an implantable putty material for delivery of active compounds to a patient.
A wide variety of implantable materials have been used in the delivery of active compounds to a patient. For example, such materials can be used in the repair of bone defects. Typically, these materials are implanted at a desired site to promote bone growth. Ideally, such a material should have the ability to adhere and conform to the implanted site and facilitate bone growth.
U.S. Pat. Nos. 5,314,476 and 5,073,373 disclose a deformable, shape-sustaining osteogenic composition comprising demineralized bone particles and a polyhydroxy compound such as glycerol, or an oligosaccharide.
U.S. Pat. Nos. 5,405,390 and 5,236,456 disclose a surface-adherent osteogenic composition derived from demineralized and thermally modified bone tissue. The composition is administered in the form of a powder, a viscous liquid, or by direct injection.
U.S. Pat. No. 5,246,457 discloses a bone-repair composition comprising a calcium phosphate salt and reconstituted fibrillar atelopeptide collagen. It does not include any biologically active ingredients. The physical and handling properties are improved by a number of curing processes, including heat, maturation of the wet mixture and/specific cross-linking of collagen.
U.S. Pat. No. 4,440,750 discloses an osteogenic composition comprising demineralized bone powder and reconstituted native atelopeptide collagen fibers in a continuous aqueous phase having a substantially physiologic pH and ionic strength.
U.S. Pat. No. 4,975,526 discloses a matrix material comprising protein-extracted demineralized bone powder and a swelling agent to increase the intraparticle porosity of the matrix.
U.S. Pat. No. 4,394,370 discloses a bone graft material for treating osseous defects. The material comprises collagen and demineralized bone particles and is sponge-like.
Currently known implantable materials, including those discussed above, are lacking in acceptable texture properties, such as cohesiveness, elasticity and the ability to be molded to a selected shape. Moreover, other paste-like materials such as those disclosed in U.S. Pat. Nos. 5,314,476 and 5,073,373 require an organic solvent such as glycerol, as discussed above.
Therefore, there is a need for an osteoinductive material which have an improved handling properties and which does not require an organic solvent.
One embodiment of the present invention is a putty material which includes collagen and water, wherein the putty material has a pH of between about 3.0 to about 6.0. Materials of the invention have excellent physical properties and handling characteristics. The collagen of the putty material can be selected from the group consisting of fibrillar collagen, atelopeptide collagen, telopeptide collagen and tropocollagen. The putty material can be formed by the addition of an acid selected from the group consisting of ascorbic acid, acetic acid, acetyl salicylic acid, benzoic acid, citric acid, glutamic acid, glycolic acid, lactic acid, malic acid, salicylic acid, and hydrochloric acid. The putty material can also include an active ingredient, such as an active ingredient selected from the group consisting of osteoinductive materials, growth factors, cartilage inducing factors, angiogenic factors, hormones, antibiotics, and antiviral compounds.
Another embodiment of the present invention is an osteogenic composition which includes collagen, an osteoinductive material, and an acid, wherein the osteogenic composition includes between about 0.05 mmol of acid per 100 mg of the collagen to about 2.3 mmol of acid per 100 mg of the collagen.
Another embodiment of the present invention is an osteogenic composition which includes bovine tendon Type I collagen, ascorbic acid, water, bone growth protein and a demineralized bone material.
Another embodiment of the present invention is a composition produced from a process including the steps of admixing collagen, an acid, and water to form a gel; and adding a demineralized bone material to said gel to produce an ost eogenic putty, wherein the osteogenic putty has a pH of about 6.0 or less.
Another embodiment of the present invention is a process for making a dry osteoinductive composition comprising the steps ofadmixing collagen, an acid, an osteoinductive material and water to form a gel; and lyophilizing said gel.
Another embodiment of the present invention is a method for administering an active compound to a patient comprising the steps of preparing a delivery vehicle by admixing collagen and an acid to form a composition having a pH of between about 3.0 and about 6.0, incorporating an active compound into the delivery vehicle and implanting the delivery vehicle in a desired portion of the patient""s body.